Yesterday I had a hard landing (ok, I swear it's a hard landing though I was flying a student rig and the video shows otherwise ) where I landed on the (I think) balls of my feet and fell forward.

Yesterday and this morning, the 'knuckles' of my feet hurt slightly. Not bad enough to bother me, but I'm curious what 1) could have happened 2) what likely happened. I've got no medical background so I just assumed it's a very minor fracture (can't be a sprain, it's not a joint right) but I'm curious what people with medical and/or skydiving background think.

I'm just curious because I think it's pretty cool to have a very minor fracture. I once fractured my toe before by kicking into something hard. Doctor just told me to rest it (no cast, no meds, nothing) and it recovered with time.

If you land on the front portion of your foot (the "ball") and roll forward your toes will extend (move "up) and one of 2 things "can" happen...

1) you can strain the muscles, tendons, and/or ligaments that support the extension of your toes (like rolling an ankle, but your toes!) 2) you can fracture the metacarpal bones usually at the "head" which can range from microfractures to severe displaced fractures. Worst case is a nasty thing called a LisFranc fracture but the mechanism is not quite the same as you described

Anyhow, if its still bothering you the easiest way to find out is an x-ray. If you're getting better usually NSAIDS (ibuprofen or naproxen) is usually enough along with preventing re injury while healing.

A third possibility is that you bruised a bone. Bone bruises heal slowly. I have bruised my heels a couple of times. The second time, the doctor told me to quit running on hard surfaces for a couple of months. The last time I bruised my sternum and ribs, it was five months before the pain went away.